An exceptionally rare, generally benign, granular cell tumor that arises from the mediastinum. All the reported cases were located in the posterior mediastinum. The disease is Monarch Disease Ontology identifier MONDO_0003255 (mediastinal granular cell myoblastoma). Also known as: granular cell myoblastoma of mediastinum, granular cell myoblastoma of the mediastinum, granular cell neoplasm of mediastinum, granular cell neoplasm of the mediastinum, granular cell tumor of mediastinum, granular cell tumor of the mediastinum, granular cell tumour of mediastinum, granular cell tumour of the mediastinum.